In existing systems, control of a vehicle such as a back hoe is achieved by manipulation of levers and more recently by joy sticks. In computer applications joy sticks are a common control system but a computer may also employ a "track ball" or a "mouse". These devices have limited directions of motion and accordingly limited commands only are possible.
In addition to a control system, there is also a need for a sensing system to monitor applied forces and torques: an example of such a sensor system is a system for monitoring applied forces and torques with respect to three axes in a manipulator (see U.S. Pat. No. 3 921 445 Hill and Sword). In that specification the manipulator is of a hand like form comprising a pair of jaws which are relatively pivotally movable under operation of an electric motor. The manipulator is defined as having a wrist and sensing means are provided for sensing the magnitude and direction of forces along three mutually orthogonal axes intersecting at the wrist and for sensing the magnitude and direction of torques about the axes. The form of the sensing means is a series of sensors extending around the longitudinal axis of the manipulator.